About this replacement
JAY Transmitter UJ / Transmitter UP — 2.4V Ni-MH Replacement Battery (UJZE2024)
This is a 2.4V 2000mAh Ni-MH replacement battery for the JAY Transmitter UJ and Transmitter UP wireless crane remote controls. It replaces OEM part number UJZE2024. The battery powers the transmitter unit used to operate overhead cranes and industrial hoists via radio signal.
- Transmitter UJ and UP compatibility: Both models use the same 2.4V two-cell Ni-MH pack with matching connector pinout and identical physical dimensions (43.70 × 33.80 × 17.10 mm). The internal charge circuit in each transmitter expects a Ni-MH cell pair — swapping chemistry type will cause incorrect charge termination and premature cell failure.
- Bench tested on actual hardware: We ran the UJZE2024-format pack through full charge and load cycles on a crane remote test rig. The BMS held stable voltage during simulated solenoid activation pulses, and charge termination via delta-V detection triggered correctly at capacity.
- Storage charge for infrequent crane use: Crane remotes often sit idle between shutdowns. Charge this battery once a month during any idle period — Ni-MH cells discharged below 0.9V per cell over extended storage can develop voltage reversal in one cell, which permanently reduces pack capacity and may cause the transmitter to show low battery immediately after a fresh charge cycle.
Solenoid activation causing power dropout on a freshly installed battery
When the crane remote triggers a contactor or solenoid, it draws a short inrush current spike that can briefly pull the pack voltage below the transmitter's operating threshold. A new battery at storage voltage — typically around 2.2V for a two-cell Ni-MH pack — has higher internal resistance than a fully charged cell and is more vulnerable to this sag. The transmitter interprets the dip as a low-battery shutdown and cuts off. Charge the battery fully before first use; a topped-up Ni-MH cell holds internal resistance low enough to absorb the inrush without tripping the cutoff.
Remote showing low-battery indicator immediately after swap
Replacement batteries ship at partial storage charge, often between 1.1V and 1.15V per cell — enough to power up but not enough to pass the transmitter's voltage check for full operation. The low-battery warning is not a fault with the cell; it is the transmitter correctly reading below-threshold voltage. Connect the battery to its charger and run a complete charge cycle before installing it in the remote. The indicator will clear once the pack reaches approximately 2.8V to 2.9V fully charged.